Methodology
How Lunch-Break Hours Are Calculated
The exact arithmetic behind a time card with an unpaid lunch — shift span, break subtraction, decimal conversion and the weekly overtime threshold.
Every time card with an unpaid lunch comes down to one subtraction: the time you were clocked in, minus the time you were at lunch. The catch is that payroll wants the answer in decimal hours, and humans read clocks in hours and minutes. Both formats are shown so you can cross-check your pay stub against your card.
shift = clock-out − clock-in (+24 h if overnight)break = lunch-in − lunch-outpaid minutes = shift − breakdecimal = paid minutes ÷ 60 → what payroll multiplies by your rate
The weekly view matters because overtime in the United States is weekly: the FLSA requires 1.5x pay above 40 paid hours in a workweek. Daily overtime rules differ — California, for example, pays overtime after 8 paid hours in a day and double time after 12. The day-by-day decimal column on the calculator lets you apply whichever rule covers you.
Auto-deduction is a policy many employers use: instead of punching out for lunch, a fixed break (commonly 30 minutes) is subtracted from every shift long enough to contain it. It is legal when it accurately reflects the break actually taken. If your lunches vary, record the actual out and in punches — that is the evidence that protects you in a wage audit.
Worked example: a full week
| Day | In → Out | Lunch | Paid (decimal) |
|---|---|---|---|
| Mon | 8:00 AM → 5:00 PM | 12:00–12:45 PM | 8.25 |
| Tue | 8:00 AM → 5:00 PM | 12:00–12:45 PM | 8.25 |
| Wed | 8:00 AM → 5:00 PM | 12:00–12:45 PM | 8.25 |
| Thu | 8:00 AM → 5:00 PM | 12:00–12:45 PM | 8.25 |
| Fri | 8:00 AM → 6:00 PM | 12:00–12:45 PM | 9.25 |
| Weekly total | 42.25 h → 2.25 h overtime | ||
